JP7696446B2 - Polypropylene resin composition and its uses - Google Patents

Description

The present invention relates to a polypropylene-based resin composition that has a low linear expansion coefficient, high dimensional stability, and can be used to produce molded articles suitable for manufacturing structures laminated with other components, and uses thereof.

Molded articles obtained by injection molding polypropylene resin compositions are increasingly being used in a variety of fields, including automobile parts and home appliance parts, due to their excellent mechanical properties and moldability, as well as their relatively favorable cost performance compared to other materials.

In the field of automotive parts, in addition to using polypropylene alone, materials with improved impact resistance due to the addition of rubber components such as ethylene-propylene copolymer (EPR), ethylene-butene copolymer (EBR), ethylene-octene copolymer (EOR), styrene-butadiene copolymer (SBR), and polystyrene-ethylene/butene-polystyrene triblock copolymer (SEBS) to polypropylene, materials with improved rigidity due to the addition of inorganic fillers such as talc, mica, and glass fiber, and blend polymers with well-balanced mechanical properties due to the addition of both rubber components and inorganic fillers are also used.

In recent years, there has been an increasing need to develop materials with excellent dimensional stability (low linear expansion coefficient) while maintaining high mechanical properties (mainly rigidity), mainly for use as a replacement for metal materials, and research and development of materials has been carried out to achieve this. However, polypropylene molded products generally have a large dimensional change (linear expansion coefficient) relative to temperature, so when used in environments with large temperature differences, such as for automobile exterior panels, there are problems such as gaps at the joints of parts or deterioration of fit when assembling parts, i.e., poor gap quality problems. As a result, the high design quality and excellent cost-effectiveness of polypropylene molded products have not yet been fully enjoyed in this field.

As a measure to improve the dimensional stability of polypropylene molded products, various propylene resin compositions have been proposed in which inorganic fillers such as talc are blended with polypropylene, elastomer components, etc. For example, there are a method for producing a low linear expansion material characterized by the combined use of a propylene block copolymer containing a crystalline polypropylene with a melt flow rate of 500 g/10 min or more and a low molecular weight polyolefin (Patent Document 1), a resin composition in which a specific ethylene-butene-1 copolymer is blended with a propylene block copolymer (Patent Document 2), a resin composition characterized by specifying the blending ratio and viscosity of the amorphous and crystalline parts of the propylene block copolymer (Patent Document 3), a resin composition characterized by using talc with an average particle size of 3 μm or less and having excellent paint appearance after injection molding (Patent Document 4), a resin composition containing a propylene-based resin produced with a Ziegler catalyst and talc of a specific shape (Patent Document 5), and a resin composition characterized by using two types of propylene block copolymers with different melt flow rates and talc of a specific shape (Patent Document 6). Furthermore, in order to further improve surface impact resistance at low temperatures, a resin composition containing a propylene block copolymer, a propylene homopolymer, an ethylene-α-olefin copolymer and an inorganic filler in specific ratios has been proposed (Patent Documents 7 and 8).

In the field of automotive parts, manufacturers are actively promoting the use of resin for exterior panel materials in response to the need to reduce the weight of automobiles. As part of this movement, the switch from metal to resin is also underway for the outer parts of back doors. From the standpoint of design, the use of resin for these exterior panel materials requires dimensional accuracy on a par with that of metal, and the material must have a low linear expansion coefficient. Furthermore, back door materials need to be bonded to other components, so high adhesive performance is also required.

However, the above-mentioned documents do not teach any means for improving the adhesive performance when molded articles made from these polypropylene-based resin compositions are bonded to other components, and conventional polypropylene-based resin compositions have not been able to produce molded articles that combine dimensional stability with high adhesive performance.

JP 2010-077396 A Japanese Patent Application Publication No. 5-051498 JP 2000-095919 A JP 2007-91789 A JP 2013-159709 A JP 2014-58614 A JP 2016-84386 A WO2017/082358

In order to achieve low linear expansion of polypropylene-based molded bodies, it is necessary to increase the amount of secondary materials with low linear expansion coefficients as mentioned above, and to further impart paintability, it is also necessary to increase the rubber content. For these reasons, polypropylene compound materials for plastic exterior panels have a very high filler and rubber content, but when they are bonded to other components, there is a problem that interfacial peeling is likely to occur at the interface between the secondary materials and the polypropylene compound material during adhesion tests, which makes it easy for strength to decrease. In addition, since polypropylene itself does not have polar functional groups, flame treatment or plasma treatment is required to create strong chemical bonds with adhesives, and this treatment causes damage to the substrate surface, which easily reduces adhesive strength, which is also a problem. To ensure this adhesive strength, it is common to use a primer, but the use of a primer increases costs and increases the number of manufacturing processes. Therefore, there is a demand for a polypropylene-based molded product and a polypropylene-based resin composition capable of producing the same, which can combine the two properties of high dimensional stability and high adhesive performance, while maintaining the low linear expansion coefficient required for exterior panel materials, and which can produce a primerless composite material having sufficient adhesive strength.

The objective of the present invention is to provide a polypropylene-based resin composition and uses thereof that can produce molded articles having a low linear expansion coefficient, excellent dimensional stability, and high adhesive strength without the need for a primer.

As a result of intensive research conducted in light of the above-mentioned circumstances, the inventors discovered that a polypropylene-based resin composition containing an ethylene-α-olefin copolymer, which has a very high melting point, as an elastomer component can be used to produce molded articles that have excellent dimensional stability and adhesion, and thus completed the present invention.

The present invention relates to the following items [1] to [8].
[1] 5 to 47 parts by mass of a propylene polymer (A) having a melt flow rate (230°C, 2.16 kg load) of 50 to 150 g/10 min and a decane soluble content of 6 to 15 mass%,
20 to 30 parts by mass of a propylene homopolymer (B) having a melt flow rate (230° C., 2.16 kg load) of 10 to 500 g/10 min,
23 to 30 parts by mass of an ethylene/α-olefin copolymer (C) which is a random copolymer of ethylene and an α-olefin having 4 to 8 carbon atoms and has a density of 0.850 to 0.880 g/cm ³ , a melt flow rate (230° C., 2.16 kg load) of 0.5 to 30 g/10 min, and a melting point peak of 110° C. or higher, and 30 to 40 parts by mass of an inorganic filler (D) (wherein the total amount of components (A) to (D) is 100 parts by mass).
A polypropylene resin composition comprising:
[2] The polypropylene-based resin composition according to [1], wherein the propylene-based polymer (A) is a block copolymer of propylene and ethylene, and the intrinsic viscosity [η] of a decane-soluble portion of the copolymer is 2 to 9 dl/g.
[3] The polypropylene resin composition according to [1] or [2], wherein the inorganic filler (D) is talc and has an aspect ratio of 3 or more and less than 15.
[4] The polypropylene resin composition according to any one of [1] to [3], characterized in that in a primerless adhesion test, the 90°C hot shear test strength exceeds 1.5 MPa.
[5] The polypropylene resin composition according to any one of [1] to [4], which is used for an automobile exterior member.
[6] A molded article comprising the polypropylene resin composition according to any one of [1] to [5].
[7] The molded article according to [6], which is an injection molded article or a press molded article.
[8] The molded article according to [6] or [7], which is an automobile exterior component.

According to the present invention, it is possible to provide a polypropylene-based resin composition and uses thereof that can produce molded articles having a low linear expansion coefficient, excellent dimensional stability, and high adhesive strength with urethane-based adhesive layers and the like without the need for a primer.

FIG. 1 is a schematic diagram of hot shear test strength measurement.

The present invention will be specifically described below.
Polypropylene resin composition
The polypropylene resin composition of the present invention contains a propylene polymer (A), a propylene homopolymer (B), an ethylene/α-olefin copolymer (C), and an inorganic filler (D), and may further contain other components as required.

<Propylene-Based Polymer (A)>
The propylene polymer (A) used in the present invention is a propylene polymer having a melt flow rate (230° C., 2.16 kg load) of 50 to 150 g/10 min and a decane soluble content of 6 to 15 mass %.

The propylene polymer (A) substantially contains 6 to 15% by mass of a decane-soluble portion (a1) and 85 to 94% by mass of a decane-insoluble portion (a2). The decane-insoluble portion (a2) is generally a component that is insoluble in n-decane solvent at room temperature (23°C), and is usually equivalent to the propylene homopolymer portion (propylene homopolymer component) in the propylene polymer (A). The decane-soluble portion (a1) is equivalent to the portion other than the propylene homopolymer portion, and is preferably a copolymer portion of propylene and ethylene (ethylene-propylene copolymer component).

The propylene polymer (A) typically contains 6 to 15 mass% of decane-soluble portion (a1) and 85 to 94 mass% of decane-insoluble portion (a2), and preferably contains 7 to 12 mass% of decane-soluble portion (a1) and 88 to 93 mass% of decane-insoluble portion (a2) [wherein the sum of the contents of (a1) and (a2) is 100 mass%].

The propylene polymer (A) is preferably a propylene block copolymer obtained from propylene and ethylene. The intrinsic viscosity [η] of the decane-soluble portion (a1) of this propylene block copolymer is preferably 2 to 9 dl/g, more preferably 3 to 8 dl/g.

The melt flow rate of the propylene polymer (A) (230°C, 2.16 kg load) is 50 to 150 g/10 min, preferably 50 to 130 g/10 min, more preferably 60 to 120 g/10 min, and particularly preferably 70 to 110 g/10 min.

The propylene polymer (A) can be produced by a known method, for example, by polymerizing propylene using an olefin polymerization catalyst containing a solid titanium catalyst component (I) and an organometallic compound catalyst component (II) described below, and then copolymerizing propylene with ethylene to obtain a propylene block copolymer.
[Solid titanium catalyst component (I)]
The solid titanium catalyst component (I) constituting the olefin polymerization catalyst contains, for example, titanium, magnesium, a halogen, and, if necessary, an electron donor. Any known components can be used for this solid titanium catalyst component (I) without any restrictions.

In the preparation of solid titanium catalyst component (I), magnesium compounds and titanium compounds are often used.

Specific examples of magnesium compounds include magnesium halides such as magnesium chloride and magnesium bromide; alkoxy magnesium halides such as methoxy magnesium chloride, ethoxy magnesium chloride, and phenoxy magnesium chloride; alkoxy magnesium such as ethoxy magnesium, isopropoxy magnesium, butoxy magnesium, and 2-ethylhexoxy magnesium; aryloxy magnesium such as phenoxy magnesium; and magnesium carboxylates such as magnesium stearate. The magnesium compounds may be used alone or in combination of two or more. The magnesium compounds may also be complex compounds or complex compounds with other metals, or mixtures with other metal compounds.

Among these, magnesium compounds containing halogens are preferred, and magnesium halides, especially magnesium chloride, are more preferred. In addition, alkoxymagnesium such as ethoxymagnesium are also preferred. The magnesium compound may also be one derived from another substance, for example, a compound obtained by contacting an organomagnesium compound such as a Grignard reagent with a titanium halide, silicon halide, or alcohol halide.

Examples of titanium compounds include tetravalent titanium compounds represented by the following formula:

Ti(OR) _{gX4 -g}
(In the formula, R is a hydrocarbon group, X is a halogen atom, and g is 0≦g≦4.)
Specific examples of titanium compounds include titanium tetrahalides such as TiCl ₄ and TiBr ₄ ; alkoxy titanium trihalides such as Ti(OCH ₃ )Cl ₃ , Ti(OC ₂ H ₅ )Cl ₃ , Ti(O-n-C ₄ H ₉ )Cl ₃ , Ti(OC ₂ H ₅ )Br ₃ and Ti(O-i-C ₄ H ₉ )Br ₃ ; alkoxy titanium dihalides such as Ti(OCH ₃ ) ₂ Cl ₂ and Ti(OC ₂ H ₅ ) ₂ Cl ₂ ; alkoxy titanium monohalides such as Ti(OCH ₃ ) ₃ Cl, Ti(O-n-C ₄ H ₉ ) ₃ Cl and Ti(OC _{2 H 5} ) _{3 Br} ; Examples of _the titanium compound include tetraalkoxy titanium such as _Ti ( _OC4H9 ) ₄ , Ti(O-2- _ethylhexyl ) _{4 ,} etc. The titanium compound may be used alone or in combination of two or more. Among them, titanium tetrahalides are preferred, and titanium tetrachloride is more preferred.

As magnesium compounds and titanium compounds, for example, compounds described in detail in JP-A-57-63310 and JP-A-5-170843 can also be used.

Specific preferred methods for preparing the solid titanium catalyst component (I) used in the present invention include the following methods (P-1) to (P-4).
(P-1) A method in which a solid adduct consisting of an electron donor component (1) such as a magnesium compound and an alcohol, an electron donor component (2) described below, and a liquid titanium compound are contacted in a suspended state in the presence of an inert hydrocarbon solvent.
(P-2) A method in which a solid adduct consisting of a magnesium compound and an electron donor component (1), an electron donor component (2), and a liquid titanium compound are contacted in separate batches.
(P-3) A method in which a solid adduct consisting of a magnesium compound and an electron donor component (1), an electron donor component (2), and a liquid titanium compound are contacted in a suspended state in the presence of an inert hydrocarbon solvent, and the contact is carried out in multiple batches.
(P-4) A method of contacting a liquid magnesium compound comprising a magnesium compound and an electron donor component (1), a liquid titanium compound, and an electron donor component (2).

The reaction temperature when preparing the solid titanium catalyst component (I) is preferably -30 to 150°C, more preferably -25 to 130°C, and particularly preferably -25 to 120°C.

The preparation of the solid titanium catalyst component (I) can be carried out in the presence of a known medium, if necessary. Specific examples of the medium include aromatic hydrocarbons such as toluene, which have a slight polarity, and known aliphatic or alicyclic hydrocarbons such as heptane, octane, decane, and cyclohexane. Among these, aliphatic hydrocarbons are preferred.

As the electron donor component (1) used to form a solid adduct or a liquid magnesium compound, a known compound capable of solubilizing a magnesium compound in a temperature range of room temperature to about 300°C is preferred, such as an alcohol, an aldehyde, an amine, a carboxylic acid, or a mixture thereof. Examples of these compounds include those described in JP-A-57-63310 and JP-A-5-170843.

Specific examples of alcohols that can solubilize magnesium compounds include aliphatic alcohols such as methanol, ethanol, propanol, butanol, isobutanol, ethylene glycol, 2-methylpentanol, 2-ethylbutanol, n-heptanol, n-octanol, 2-ethylhexanol, decanol, and dodecanol; alicyclic alcohols such as cyclohexanol and methylcyclohexanol; aromatic alcohols such as benzyl alcohol and methylbenzyl alcohol; and aliphatic alcohols having alkoxy groups such as n-butyl cellosolve.

Specific examples of carboxylic acids include organic carboxylic acids having 7 or more carbon atoms, such as caprylic acid and 2-ethylhexanoic acid.Specific examples of aldehydes include aldehydes having 7 or more carbon atoms, such as capric aldehyde and 2-ethylhexyl aldehyde.Specific examples of amines include amines having 6 or more carbon atoms, such as heptylamine, octylamine, nonylamine, laurylamine, and 2-ethylhexylamine.

As the electron donor component (1), the above-mentioned alcohols are preferred, and in particular ethanol, propanol, butanol, isobutanol, hexanol, 2-ethylhexanol, and decanol are preferred.

The composition ratio of magnesium to electron donor component (1) in the resulting solid adduct or liquid magnesium compound varies depending on the type of compound used and cannot be generally defined, but the amount of electron donor component (1) per mole of magnesium in the magnesium compound is preferably 2 moles or more, more preferably 2.3 moles or more, and particularly preferably 2.7 moles or more and 5 moles or less.

Particularly preferred examples of electron donors that may be used as needed in the solid titanium catalyst component (I) include aromatic carboxylic acid esters and/or compounds having two or more ether bonds via multiple carbon atoms (hereinafter referred to as "electron donor component (2)").

As the electron donor component (2), known aromatic carboxylic acid esters and polyether compounds that have been preferably used in conventional olefin polymerization catalysts, such as the compounds described in JP-A-5-170843 and JP-A-2001-354714, can be used without restriction.

Specific examples of aromatic carboxylate esters include aromatic carboxylate monoesters such as benzoate esters and toluate esters, as well as aromatic polycarboxylic acid esters such as phthalate esters. Among these, aromatic polycarboxylic acid esters are preferred, and phthalate esters are more preferred. As the phthalate esters, alkyl phthalates such as ethyl phthalate, n-butyl phthalate, isobutyl phthalate, hexyl phthalate, and heptyl phthalate are preferred, and diisobutyl phthalate is particularly preferred.

Specific examples of polyether compounds include compounds represented by the following chemical structural formula (1).

上記式（１）中、ｍは１≦ｍ≦１０の整数、より好ましくは３≦ｍ≦１０の整数であり、Ｒ¹¹～Ｒ³⁶は、それぞれ独立に、水素原子、あるいは炭素、水素、酸素、フッ素、塩素、臭素、ヨウ素、窒素、硫黄、リン、ホウ素及びケイ素から選択される少なくとも１種の元素を有する置換基である。ｍが２以上である場合、複数個存在するＲ¹¹及びＲ¹²は、それぞれ同じであっても異なっていてもよい。任意のＲ¹¹～Ｒ³⁶、好ましくはＲ¹¹及びＲ¹²は共同してベンゼン環以外の環を形成していてもよい。

In the above formula (1), m is an integer of 1≦m≦10, more preferably an integer of 3≦m≦10, and R ¹¹ to R ³⁶ are each independently a hydrogen atom or a substituent having at least one element selected from carbon, hydrogen, oxygen, fluorine, chlorine, bromine, iodine, nitrogen, sulfur, phosphorus, boron and silicon. When m is 2 or more, the multiple R ¹¹ and R ¹² may be the same or different. Any of R ¹¹ to R ³⁶ , preferably R ¹¹ and R ¹² , may join together to form a ring other than a benzene ring.

Specific examples of such compounds include mono-substituted dialkoxypropanes such as 2-isopropyl-1,3-dimethoxypropane, 2-s-butyl-1,3-dimethoxypropane, and 2-cumyl-1,3-dimethoxypropane; 2-isopropyl-2-isobutyl-1,3-dimethoxypropane, 2,2-dicyclohexyl-1,3-dimethoxypropane, 2-methyl-2-isopropyl-1,3-dimethoxypropane, and 2-methyl-2-cyclohexyl-1,3-dimethoxypropane. Methoxypropane, 2-methyl-2-isobutyl-1,3-dimethoxypropane, 2,2-diisobutyl-1,3-dimethoxypropane, 2,2-bis(cyclohexylmethyl)-1,3-dimethoxypropane, 2,2-diisobutyl-1,3-diethoxypropane, 2,2-diisobutyl-1,3-dibutoxypropane, 2,2-di-s-butyl-1,3-dimethoxypropane, 2,2-dineopentyl-1,3-dimethoxypropane, 2-isopropyl -2-isopentyl-1,3-dimethoxypropane, 2-cyclohexyl-2-cyclohexylmethyl-1,3-dimethoxypropane and other 2-substituted dialkoxypropanes; 2,3-dicyclohexyl-1,4-diethoxybutane, 2,3-dicyclohexyl-1,4-diethoxybutane, 2,3-diisopropyl-1,4-diethoxybutane, 2,4-diphenyl-1,5-dimethoxypentane, 2,5-diphenyl-1,5-dimethoxyhexane, 2,4 2-Diisopropyl-1,5-dimethoxypentane, 2,4-diisobutyl-1,5-dimethoxypentane, 2,4-diisoamyl-1,5-dimethoxypentane, and other dialkoxyalkanes; 2-methyl-2-methoxymethyl-1,3-dimethoxypropane, 2-cyclohexyl-2-ethoxymethyl-1,3-diethoxypropane, 2-cyclohexyl-2-methoxymethyl-1,3-dimethoxypropane, and other trialkoxyalkanes. The polyether compounds may be used alone or in combination of two or more. Of these, 1,3-diethers are preferred, and 2-isopropyl-2-isobutyl-1,3-dimethoxypropane, 2,2-diisobutyl-1,3-dimethoxypropane, 2-isopropyl-2-isopentyl-1,3-dimethoxypropane, 2,2-dicyclohexyl-1,3-dimethoxypropane, and 2,2-bis(cyclohexylmethyl)-1,3-dimethoxypropane are particularly preferred.

In the solid titanium catalyst component (I), the halogen/titanium (atomic ratio) (i.e., the number of moles of halogen atoms/the number of moles of titanium atoms) is 2 to 100, preferably 4 to 90, the electron donor component (1)/titanium atom (molar ratio) is 0 to 100, preferably 0 to 10, and the electron donor component (2)/titanium atom (molar ratio) is 0 to 100, preferably 0 to 10. The magnesium/titanium (atomic ratio) (i.e., the number of moles of magnesium atoms/the number of moles of titanium atoms) is 2 to 100, preferably 4 to 50.

As more detailed preparation conditions for the solid titanium catalyst component (I), other than the use of the electron donor component (2), the conditions described in, for example, EP 585869 A1 and JP-A-5-170843 can be suitably used.

[Organometallic compound catalyst component (II)]
The organometallic compound catalyst component (II) is a component containing a metal element selected from Groups 1, 2, and 13 of the periodic table. For example, a compound containing a Group 13 metal (such as an organoaluminum compound), an alkyl complex of a Group 1 metal and aluminum, an organometallic compound of a Group 2 metal, etc. can be used. Among these, an organoaluminum compound is preferred.

As the organometallic compound catalyst component (II), specifically, the organometallic compound catalyst components described in known documents such as the above-mentioned EP 585869 A1 can be suitably used.

As long as the objective of the present invention is not impaired, in addition to the electron donor component (1) and electron donor component (2) described above, a known electron donor component (3) may be used in combination.

As the electron donor component (3), an organosilicon compound is preferred. The organosilicon compound is, for example, a compound represented by the following formula:

R _n Si(OR') _4-n
(In the formula, R and R′ are hydrocarbon groups, and n is an integer of 0<n<4.)
Specific examples of the organosilicon compound represented by the above formula include diisopropyldimethoxysilane, t-butylmethyldimethoxysilane, t-butylmethyldiethoxysilane, t-amylmethyldiethoxysilane, dicyclohexyldimethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, t-butyltriethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, cyclohexyltrimethoxysilane, cyclopentyltrimethoxysilane, 2-methylcyclopentyltrimethoxysilane, cyclopentyltriethoxysilane, dicyclopentyldimethoxysilane, dicyclopentyldiethoxysilane, tricyclopentylmethoxysilane, dicyclopentylmethylmethoxysilane, dicyclopentylethylmethoxysilane, and cyclopentyldimethylethoxysilane. Of these, vinyltriethoxysilane, diphenyldimethoxysilane, dicyclohexyldimethoxysilane, cyclohexylmethyldimethoxysilane, and dicyclopentyldimethoxysilane are preferred.

Additionally, the silane compound represented by the following formula, described in International Publication No. 2004/016662, is also a preferred example of an organosilicon compound.

Si(OR ^a ) ₃ (NR ^b R ^c )
In the above formula, R ^a is a hydrocarbon group having 1 to 6 carbon atoms. For example, it is an unsaturated or saturated aliphatic hydrocarbon group having 1 to 6 carbon atoms, and a hydrocarbon group having 2 to 6 carbon atoms is particularly preferred. Specific examples include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, an n-pentyl group, an iso-pentyl group, a cyclopentyl group, an n-hexyl group, and a cyclohexyl group. Of these, an ethyl group is particularly preferred.

R ^b is a hydrocarbon group having 1 to 12 carbon atoms or hydrogen. For example, it is an unsaturated or saturated aliphatic hydrocarbon group having 1 to 12 carbon atoms or hydrogen. Specific examples include a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, an n-pentyl group, an iso-pentyl group, a cyclopentyl group, an n-hexyl group, a cyclohexyl group, and an octyl group. Of these, an ethyl group is particularly preferable.

^Rc is a hydrocarbon group having 1 to 12 carbon atoms. For example, it is an unsaturated or saturated aliphatic hydrocarbon group having 1 to 12 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, an n-pentyl group, an iso-pentyl group, a cyclopentyl group, an n-hexyl group, a cyclohexyl group, and an octyl group. Of these, an ethyl group is particularly preferable.

Specific examples of organosilicon compounds represented by the above formula include dimethylaminotriethoxysilane, diethylaminotriethoxysilane, diethylaminotrimethoxysilane, diethylaminotri-n-propoxysilane, di-n-propylaminotriethoxysilane, methyl n-propylaminotriethoxysilane, t-butylaminotriethoxysilane, ethyl n-propylaminotriethoxysilane, ethyl iso-propylaminotriethoxysilane, methylethylaminotriethoxysilane, etc.

Further examples of organosilicon compounds include compounds represented by the following formula:

RNSi( ^ORa ) ₃
In the above formula, R is a cyclic amino group. Specific examples include a perhydroquinolino group, a perhydroisoquinolino group, a 1,2,3,4-tetrahydroquinolino group, a 1,2,3,4-tetrahydroisoquinolino group, and an octamethyleneimino group. R ^a is the same as above.

Specific examples of the organosilicon compound represented by the above formula include (perhydroquinolino)triethoxysilane, (perhydroisoquinolino)triethoxysilane, (1,2,3,4-tetrahydroquinolino)triethoxysilane, (1,2,3,4-tetrahydroisoquinolino)triethoxysilane, octamethyleneiminotriethoxysilane, and the like.
The organosilicon compounds described above may be used in combination of two or more kinds.

[polymerization]
The propylene-ethylene block copolymer, which is a preferred embodiment of the propylene polymer (A), can be produced by a method in which propylene is polymerized in the presence of the above-mentioned olefin polymerization catalyst and then copolymerized with propylene and ethylene, or propylene is polymerized in the presence of a prepolymerization catalyst obtained by prepolymerization and then copolymerized with propylene and ethylene.

Prepolymerization is carried out by prepolymerizing an olefin in an amount of usually 0.1 to 1000 g, preferably 0.3 to 500 g, and particularly preferably 1 to 200 g per gram of olefin polymerization catalyst. In prepolymerization, a catalyst with a higher concentration can be used than the catalyst concentration in the system for main polymerization.

The concentration of the solid titanium catalyst component (I) in the preliminary polymerization is usually 0.001 to 200 millimoles, preferably 0.01 to 50 millimoles, and more preferably 0.1 to 20 millimoles, calculated as titanium atoms per liter of liquid medium.

The amount of organometallic compound catalyst component (II) in the preliminary polymerization may be an amount that produces usually 0.1 to 1000 g, preferably 0.3 to 500 g, of polymer per gram of solid titanium catalyst component (I), and is usually 0.1 to 300 mol, preferably 0.5 to 100 mol, more preferably 1 to 50 mol per mole of titanium atom in the solid titanium catalyst component (I).

In the preliminary polymerization, the above-mentioned electron donor components can be used if necessary, and in this case, these components are usually 0.1 to 50 moles, preferably 0.5 to 30 moles, and more preferably 1 to 10 moles per mole of titanium atoms in the solid titanium catalyst component (I).

Prepolymerization can be carried out under mild conditions by adding the olefin and the above catalyst components to an inert hydrocarbon medium. When an inert hydrocarbon medium is used, prepolymerization is preferably carried out in a batch manner.

Specific examples of inert hydrocarbon media include aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene; alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, cycloheptane, methylcycloheptane, and cyclooctane; aromatic hydrocarbons such as benzene, toluene, and xylene; halogenated hydrocarbons such as ethylene chloride and chlorobenzene; or mixtures of these. Among these, aliphatic hydrocarbons are preferred.

Prepolymerization can also be carried out using the olefin itself as a solvent. Prepolymerization can also be carried out substantially in the absence of a solvent. In this case, it is preferable to carry out the prepolymerization continuously.

The olefin used in the preliminary polymerization may be the same as or different from the olefin used in the main polymerization described below. Propylene is particularly preferred as the olefin.

The temperature during prepolymerization is usually -20 to 100°C, preferably -20 to 80°C, and more preferably 0 to 40°C.

Next, we will explain the main polymerization, which is carried out after or without preliminary polymerization.

This polymerization is divided into a process for producing a propylene homopolymer component and a process for producing a propylene-ethylene copolymer component.

The main polymerization (and preliminary polymerization) can be carried out by any of liquid phase polymerization methods such as bulk polymerization, solution polymerization, and suspension polymerization, or gas phase polymerization methods. As the process for producing the propylene homopolymer component, liquid phase polymerization methods such as bulk polymerization and suspension polymerization, or gas phase polymerization methods are preferred. As the process for producing the propylene-ethylene copolymer component, liquid phase polymerization methods such as bulk polymerization and suspension polymerization, or gas phase polymerization methods are preferred, with gas phase polymerization methods being more preferred.

When this polymerization is carried out in the form of a slurry polymerization reaction, the reaction solvent can be the inert hydrocarbon used in the preliminary polymerization described above, or an olefin that is liquid at the reaction temperature and pressure.

In this polymerization, the solid titanium catalyst component (I) is usually used in an amount of 0.0001 to 0.5 millimoles, preferably 0.005 to 0.1 millimoles, calculated as titanium atoms per liter of polymerization volume. The organometallic compound catalyst component (II) is usually used in an amount of 1 to 2000 moles, preferably 5 to 500 moles, per mole of titanium atoms in the prepolymerized catalyst component in the polymerization system. When an electron donor component is used, it is usually used in an amount of 0.001 to 50 moles, preferably 0.01 to 30 moles, more preferably 0.05 to 20 moles, per mole of the organometallic compound catalyst component (II).

If this polymerization is carried out in the presence of hydrogen, the molecular weight of the resulting polymer can be adjusted (reduced), resulting in a polymer with a high melt flow rate (MFR). The amount of hydrogen required to adjust the molecular weight varies depending on the type of manufacturing process used, the polymerization temperature, and the pressure, so it can be adjusted appropriately.

In the process for producing the propylene homopolymer component, the MFR can be adjusted by adjusting the polymerization temperature and amount of hydrogen. Also, in the process for producing the propylene-ethylene copolymer component, the intrinsic viscosity can be adjusted by adjusting the polymerization temperature, pressure, and amount of hydrogen.

In this polymerization, the polymerization temperature of the olefin is usually 0 to 200° C., preferably 30 to 100° C., and more preferably 50 to 90° C. The pressure (gauge pressure) is usually normal pressure to 100 kgf/cm ² (9.8 MPa), and preferably 2 to 50 kgf/cm ² (0.20 to 4.9 MPa).

In the production of a propylene-ethylene block copolymer, which is a preferred embodiment of the propylene polymer (A), the polymerization can be carried out by any of the batch, semi-continuous, and continuous methods. Furthermore, the reactor shape can be either tubular or tank type. Furthermore, the polymerization can be carried out in two or more stages by changing the reaction conditions. In this case, the tubular type and tank type can be combined.

In order to obtain a propylene-ethylene copolymer portion in a propylene-ethylene block copolymer, which is a preferred embodiment of the propylene-based polymer (A), the ethylene/(ethylene + propylene) gas ratio is controlled in the polymerization step 2 described below. The ethylene/(ethylene + propylene) gas ratio is usually 5 to 80 mol%, preferably 10 to 70 mol%, and more preferably 15 to 60 mol%.

As described above, the decane-insoluble portion (a2) of the propylene-ethylene block copolymer is mainly composed of a propylene homopolymer component. On the other hand, the decane-soluble portion (a1) is mainly composed of an ethylene-propylene copolymer component, which is a rubber-like component. For example, a propylene-ethylene block copolymer, which is a preferred embodiment of the propylene-based polymer (A), can be obtained by continuously carrying out the following two polymerization steps 1 and 2.
(Polymerization step 1)
A process for polymerizing propylene in the presence of a solid titanium catalyst component to produce a propylene homopolymer component (propylene homopolymer production process).
(Polymerization step 2)
A process for producing an ethylene-propylene copolymer component by copolymerizing propylene and ethylene in the presence of a solid titanium catalyst component (copolymer rubber production process).

In particular, it is more preferable to carry out polymerization step 1 in the first stage and polymerization step 2 in the second stage. Each of polymerization steps 1 and 2 can be carried out using two or more polymerization tanks. The content of the decane-soluble portion (a1) can be adjusted by the polymerization time (residence time) of polymerization step 1 and polymerization step 2. Furthermore, polymerization step 1 in the first stage may be carried out in two or more polymerization tanks connected in series. In that case, the ratio of propylene to hydrogen in each stage may be different for each polymerization tank.

The propylene-based polymer (A) used in the present invention may contain one or more biomass-derived monomers. The same type of monomer constituting the polymer may be only biomass-derived monomers, or may contain both biomass-derived monomers and fossil fuel-derived monomers. The biomass-derived monomer is a monomer made from any renewable natural raw material, such as plant-derived or animal-derived, including fungi, yeast, algae, and bacteria, and its residue, and contains ^14C isotope as carbon at a ratio of about ^10-12 , and has a biomass carbon concentration (pMC) of about 100 (pMC) measured in accordance with ASTM D 6866. The biomass-derived monomer is obtained by a conventionally known method. It is preferable that the propylene-based polymer (A) used in the present invention contains a biomass-derived monomer from the viewpoint of reducing environmental load. If the polymer production conditions such as the polymerization catalyst and polymerization temperature are the same, even if the raw material olefin contains a biomass-derived olefin, the molecular structure other than ^{the 14C} isotope at a ratio of about ^10-12 is the same as that of a propylene-based polymer made of a fossil fuel-derived monomer. Therefore, the performance is said to be unchanged.

In addition, the propylene-based polymer (A) according to the present invention may contain propylene derived from chemical recycling. The propylene constituting the polymer may be only propylene derived from chemical recycling, or may contain propylene derived from chemical recycling and propylene derived from fossil fuels and/or propylene derived from biomass. The propylene derived from chemical recycling is obtained by a conventionally known method. It is preferable that the propylene-based polymer (A) according to the present invention contains propylene derived from chemical recycling from the viewpoint of reducing the environmental load (mainly reducing waste). Even if the raw material monomer contains a monomer derived from chemical recycling, the monomer derived from chemical recycling is a monomer obtained by depolymerizing or pyrolyzing a polymer such as waste plastic back to a monomer unit such as propylene, and a monomer produced using the monomer as a raw material. Therefore, if the polymer production conditions such as the polymerization catalyst, polymerization process, and polymerization temperature are the same, the molecular structure is the same as that of a propylene homopolymer made of a monomer derived from a fossil fuel. Therefore, the performance is said to be the same.

<Propylene homopolymer (B)>
The propylene homopolymer (B) used in the present invention is a propylene homopolymer having a melt flow rate (230° C., 2.16 kg load) of 10 to 500 g/10 min.

The propylene homopolymer (B) may be a polymer in which substantially only propylene is polymerized. For example, a homopolymer in which only propylene is polymerized, or a crystalline polymer in which propylene is copolymerized with 6 mol % or less, preferably 3 mol % or less, of another α-olefin can be used. Among these, a homopolymer in which only propylene is polymerized is preferred.

Propylene homopolymer (B) can be produced by polymerizing a monomer mainly composed of propylene by a known method. For example, it can be obtained by polymerizing a monomer mainly composed of propylene in the presence of an olefin polymerization catalyst containing the solid titanium catalyst component (I) and the organometallic compound catalyst component (II) described above, or a combination catalyst of titanium trichloride and an alkylaluminum compound, usually called a Ziegler-Natta type catalyst. The polymerization reaction may be carried out in a continuous manner or in a batch manner. For example, it can be suitably produced by carrying out only the polymerization step 1 described above.

In the polymerization reaction, the polymerization temperature is usually 0 to 200° C., preferably 30 to 100° C., and more preferably 50 to 90° C. The pressure (gauge pressure) is usually normal pressure to 100 kgf/cm ² (9.8 MPa), and preferably 2 to 50 kgf/cm ² (0.20 to 4.9 MPa).

The melt flow rate of propylene homopolymer (B) (230°C, 2.16 kg load) is 10 to 500 g/10 min, preferably 10 to 300 g/10 min, and more preferably 20 to 250 g/10 min.

The propylene homopolymer (B) may be one type of polymer, or any combination of two or more types of propylene homopolymers may be used as long as the overall melt flow rate satisfies the above range.

The propylene homopolymer (B) used in the present invention may contain biomass-derived propylene. The propylene constituting the polymer may be only biomass-derived propylene, or may contain both biomass-derived propylene and fossil fuel-derived propylene. Biomass-derived propylene is a monomer made from any renewable natural raw material, such as plant-derived or animal-derived, including fungi, yeast, algae, and bacteria, and its residue, and contains ^{about 10-12} of 14C isotope as carbon, and has a biomass carbon concentration (pMC) of about 100 (pMC) measured in accordance with ASTM D 6866. Biomass-derived propylene is obtained by a conventionally known method. It is preferable that the propylene homopolymer (B) used in the present invention contains a biomass-derived monomer from the viewpoint of reducing the environmental load. If the polymerization catalyst, polymerization temperature, and other polymer production conditions are the same, even if the raw propylene contains biomass-derived propylene, the molecular structure is the same as that of propylene homopolymer made from fossil fuel-derived propylene, except for the fact that it contains about ^10-12 of ^14C isotope. Therefore, the performance is said to be the same.

The propylene homopolymer (B) used in the present invention may contain propylene derived from chemical recycling as a monomer, similar to the above-mentioned propylene-based polymer (A). That is, the propylene constituting the polymer may be only propylene derived from chemical recycling, or may contain propylene derived from chemical recycling and propylene derived from fossil fuels and/or propylene derived from biomass.

<Ethylene/α-olefin copolymer (C)>
The ethylene/α-olefin copolymer (C) used in the present invention is a random copolymer of ethylene and an α-olefin having 4 to 8 carbon atoms, and is an ethylene/α-olefin copolymer having a density of 0.850 to 0.880 g/cm ³ , a melt flow rate (230° C., 2.16 kg load) of 0.5 to 30 g/10 minutes, and a melting point peak of 110° C. or higher. This ethylene/α-olefin copolymer (C) is expected to contribute to improving the dimensional stability (reducing the linear expansion coefficient) of molded articles obtained from the resin composition through a synergistic effect with other components, and also contributes to improving other physical properties, resulting in a molded article with a high level of balance in physical properties.

As the α-olefin having 4 to 8 carbon atoms constituting the ethylene/α-olefin copolymer (C), 1-butene, 1-hexene, and 1-octene are preferred. The α-olefins may be used alone or in combination of two or more. As the ethylene/α-olefin copolymer (C), ethylene-octene copolymers and ethylene-butene copolymers are particularly preferred.

The melt flow rate of the ethylene/α-olefin copolymer (C) (230°C, 2.16 kg load) is 0.5 to 30 g/10 min, preferably 1 to 25 g/10 min, and more preferably 2 to 20 g/10 min.

If the melt flow rate (230°C, 2.16 kg load) of the ethylene/α-olefin copolymer (C) is 0.5 g/10 min or more, the polypropylene resin composition is less likely to have a reduced fluidity or poor dispersion during kneading, and the physical properties such as impact resistance and the surface appearance of the molded article are less likely to deteriorate. Also, if the melt flow rate (230°C, 2.16 kg load) is 30 g/10 min or less, the molded article obtained from the resin composition tends to have sufficient impact resistance.

The density of the ethylene/α-olefin copolymer (C) is from 0.850 to 0.880 g/cm ³ , and preferably from 0.855 to 0.875 g/cm ³ .

The melting peak of the ethylene/α-olefin copolymer (C) is 110°C or higher, preferably 110 to 130°C. The melting peak refers to a value determined by a differential scanning calorimeter (DSC). Specifically, the temperature at the maximum peak position when the endothermic curve of the differential scanning calorimeter (DSC) is determined can be determined as the melting peak (Tm). When the melting peak of the ethylene/α-olefin copolymer (C) satisfies the above-mentioned high temperature range, a molded article made of a polypropylene resin composition containing the copolymer has excellent adhesive strength with a curable resin layer formed from a urethane adhesive.

<Inorganic filler (D)>
The inorganic filler (D) used in the present invention may be a known inorganic filler, and is not particularly limited, but examples thereof include talc, calcium carbonate, natural mica, synthetic mica, wollastonite, montmorillonite, etc. The inorganic filler (D) may be used alone or in combination of two or more. Among them, talc is preferred. By including the inorganic filler (D) in the polypropylene resin composition of the present invention, the mechanical properties of the molded article obtained from the resin composition are excellent.

The inorganic filler (D) may be any filler that is dispersed in the resin composition, and is not particularly limited, but its average particle size is, for example, 1 μm to 20 μm, preferably more than 3.0 μm and 10.0 μm or less, preferably 3.0 μm to 8.0 μm, and more preferably 3.0 μm to 7.0 μm. This average particle size is a value measured by a laser diffraction method. Specifically, it is the particle size at an integrated value of 50% in the particle size distribution determined by a particle size distribution meter such as a laser diffraction scattering type particle size distribution meter, and examples of measuring devices include the MT3300EXII manufactured by Microtrac and the LA-920 model manufactured by Horiba, Ltd.

The aspect ratio of the inorganic filler (D) is not particularly limited, but is usually 3 or more and less than 15, preferably 4 to 13, and more preferably 5 to 11. In general, the aspect ratio is a value that represents the ratio of the long diameter to the thickness of the filler, or the ratio of the long side to the short side. If this aspect ratio is 3 or more, the rigidity and dimensional stability of the molded body tend not to decrease. Also, if it is less than 15, the balance of the mechanical properties tends not to decrease, and furthermore, the impact resistance strength tends not to decrease. Specifically, this aspect ratio is a value obtained by taking a photograph using an electron microscope, measuring the long diameter and thickness of the powder, calculating the average value, and calculating the ratio of the average particle size/average thickness.

The inorganic filler (D) contributes to improving the dimensional stability (reducing the linear expansion coefficient) of the molded body obtained from the resin composition, and also contributes to improving mechanical properties such as rigidity and impact strength. When the inorganic filler (D) has the above-mentioned average particle size (and aspect ratio), it is preferable because the synergistic effect with other components makes it easy to achieve a high level of physical property balance, particularly excellent dimensional stability, rigidity, and impact strength.

As the inorganic filler (D), inorganic fillers in any shape, such as granular, plate-like, rod-like, fibrous, whisker-like, etc., can be used. Inorganic fillers commercially available as fillers for polymers can also be used. In addition to the general powder and roving shapes, chopped strand, compressed solid, pellet (granulated) and granular shapes that are easier to handle can also be used. Among these, powder, compressed solid and granular shapes are preferred.

The inorganic filler (D) may be a mixture of two or more inorganic fillers.

The method for producing the inorganic filler (D) is not particularly limited, and it can be produced by various known methods. When talc is used as the inorganic filler (D), for example, talc having a specific average particle size and aspect ratio can be produced by pulverization or granulation. Specifically, for example, talc ore is pulverized with an impact pulverizer or a micron mill type pulverizer, and then further pulverized with a jet mill, and classified with a cyclone or a micron separator. The aspect ratio and average particle size of the talc can be appropriately adjusted by the pulverizing device and pulverization time, and talc with a controlled shape can be obtained by classification as necessary.

As the inorganic filler (D), the one obtained by crushing raw stones may be used directly, or at least a part of the filler may be surface-treated. For the surface treatment, various surface treatment agents such as organic titanate coupling agents, organic silane coupling agents, unsaturated carboxylic acids or modified polyolefins grafted with their anhydrides, fatty acids, fatty acid metal salts, fatty acid esters, etc. may be used. One type of surface treatment agent may be used alone, or two or more types may be used in combination.

The polypropylene resin composition according to the present invention may contain other additives such as nucleating agents, heat stabilizers, antistatic agents, weather stabilizers, light stabilizers, antioxidants, antioxidants, fatty acid metal salts, softeners, dispersants, fillers, colorants, lubricants, pigments, etc., as necessary, within the scope of the present invention. The additives may be mixed in any order, and may be mixed simultaneously, or a multi-stage mixing method may be used in which some components are mixed and then other components are mixed.
<Polypropylene Resin Composition>
The polypropylene resin composition according to the present invention contains 5 to 47 parts by mass of a propylene polymer (A), 20 to 30 parts by mass of a propylene homopolymer (B), 23 to 30 parts by mass of an ethylene-α-olefin copolymer (C), and 30 to 40 parts by mass of an inorganic filler (D) (wherein the total amount of components (A) to (D) is 100 parts by mass).

The polypropylene resin composition according to the present invention preferably contains 7 to 35 parts by mass of a propylene polymer (A), 20 to 30 parts by mass of a propylene homopolymer (B), 23 to 28 parts by mass of an ethylene-α-olefin copolymer (C), and 32 to 40 parts by mass of an inorganic filler (D) (wherein the total amount of components (A) to (D) is 100 parts by mass).

The polypropylene resin composition according to the present invention more preferably contains 8 to 28 parts by mass of a propylene polymer (A), 23 to 30 parts by mass of a propylene homopolymer (B), 24 to 28 parts by mass of an ethylene-α-olefin copolymer (C), and 33 to 38 parts by mass of an inorganic filler (D) (wherein the total amount of components (A) to (D) is 100 parts by mass).

The polypropylene resin composition according to the present invention particularly preferably contains 10 to 22 parts by mass of a propylene polymer (A), 25 to 30 parts by mass of a propylene homopolymer (B), 24 to 27 parts by mass of an ethylene-α-olefin copolymer (C), and 34 to 37 parts by mass of an inorganic filler (D) (wherein the total amount of components (A) to (D) is 100 parts by mass).

The polypropylene resin composition according to the present invention can be produced by blending the above-mentioned components (A) to (D) and, if necessary, optional components such as additives. The components may be blended sequentially in any order, or may be mixed simultaneously. A multi-stage mixing method may be adopted in which some components are mixed and then other components are mixed. Specifically, for example, the polypropylene resin composition can be produced by first blending the resin components (organic compound components) in the polypropylene resin composition, that is, components (A) to (C), and then adding and blending component (D) and optional components such as additives if necessary.

Methods for blending the components include, for example, mixing or melt-kneading the components simultaneously or sequentially using a mixing device such as a Banbury mixer, a single-screw extruder, a twin-screw extruder, or a high-speed twin-screw extruder.

The polypropylene resin composition of the present invention has a melt flow rate (230° C., 2.16 kg load) of usually 23 g/10 min or more, preferably more than 23 g/10 min and 50 g/10 min or less. By setting the melt flow rate in this range, the moldability is improved and deterioration of the coating appearance after injection molding can be suppressed.
The polypropylene resin composition of the present invention can be suitably used in various fields, such as automobile interior and exterior parts (particularly automobile exterior parts) and home appliance parts.

Molded article made of polypropylene resin composition The molded article made of the polypropylene resin composition of the present invention is a molded article obtained from the polypropylene resin composition of the present invention described above. Such a molded article of the present invention can be obtained by appropriately molding the polypropylene resin composition of the present invention. The molding method of the polypropylene resin composition is not particularly limited, and various methods known as molding methods for resin compositions can be used. As the molding method of the molded article of the present invention, injection molding and press molding are particularly preferred.

The molded article of the present invention has a low linear expansion coefficient, small dimensional change due to temperature change, excellent dimensional stability, and excellent adhesion to curable resins. The molded article of the present invention has excellent adhesion to curable resins having urethane bonds, and in particular exhibits high adhesive strength even without a primer (primerless) between the molded article and a curable resin layer formed from a urethane adhesive.

Specifically, when the surface of the molded article is subjected to a surface treatment as necessary, and a curable resin layer is formed by curing a urethane adhesive containing a urethane prepolymer with a polyether skeleton and an aliphatic isocyanate derivative, without using a primer, the 90°C hot shear test strength (tensile speed 50 mm/min) measured in a primerless adhesion test conforming to JIS K6850:1999 is usually 1.2 MPa or more, preferably more than 1.5 MPa, more preferably more than 2.0 MPa, and even more preferably 2.5 MPa or more, showing excellent adhesive strength.

The molded article of the present invention can be suitably used as automobile interior materials such as door trims, instrument panels, ceilings, console boxes, pillars, glove boxes, etc.; automobile exterior parts such as bumpers, side guards, air spoilers, side protectors, fenders, door panels, back doors, etc.; industrial parts such as home appliance parts, building materials, etc. Furthermore, since the molded article of the present invention has excellent adhesion to curable resins having urethane bonds, it can be suitably used as a raw material for composite members with other members, such as laminates with curable resins having urethane bonds, and laminates laminated with other members via urethane adhesives, and can be particularly suitably used for automobile exterior member applications such as back doors.

The present invention will be explained in more detail below based on examples, but the present invention is not limited to these examples.

The physical properties were measured and evaluated by the following methods.
[Melt flow rate (MFR) (g/10 min)]
The measurement was performed in accordance with ISO 1133 under conditions of a test load of 2.16 kg and a test temperature of 230°C.
[Decane solubles ( _Dsol ) and insolubles ( _Dinsol )]
A glass measuring vessel was charged with about 3 g of sample [component (A)] (measured to the nearest 10 ⁻⁴ g. This mass was expressed as x ₂ (g) in the formula below), 500 ml of n-decane, and a small amount of a heat-resistant stabilizer soluble in n-decane. The vessel was heated to 150° C. over 2 hours while stirring with a stirrer under a nitrogen atmosphere to dissolve the sample, and the vessel was held at 150° C. for 2 hours and then slowly cooled to 23° C. over 8 hours. The resulting liquid containing the precipitate was filtered under reduced pressure using a glass filter of 25G-4 standard manufactured by Iwata Glass Co., Ltd. 100 ml of the filtrate was collected and dried under reduced pressure to obtain a part of the decane-soluble component, and the mass was measured to the nearest 10 ⁻⁴ g (this mass was expressed as x ₁ (g) in the formula below). Using these measured values, the amount of decane-soluble part (D _sol ) and the amount of insoluble part (D _insol ) at room temperature (i.e., 23° C.) were determined according to the formula below.
D _sol (mass%) = 100×(500×x ₁ )/(100×x ₂ )
D _insol (mass%) = 100-D _sol

[Melting point peak]
An endothermic curve is obtained by a differential scanning calorimeter (DSC), and the temperature at the maximum peak position is determined as the melting point peak (Tm).
The measuring machine used was Pyris 1 manufactured by PerkinElmer Co., Ltd. The sample was packed in an aluminum pan, held at 30°C for 1 minute, heated to 160°C at 500°C/min, held at 160°C for 5 minutes, cooled to -30°C at 10°C/min, and then heated from -30°C to 160°C at 10°C/min, from which the melting point peak (Tm) was determined from the endothermic curve obtained.
[Average particle size of inorganic filler]
In accordance with JIS R1620 and JIS R1622, the particle size value at a cumulative amount of 50% by mass read from a particle size cumulative curve measured by a laser diffraction method was taken as the average particle size.
[Aspect ratio of inorganic filler]
Photographs were taken using an electron microscope, the major axis (particle size) and thickness of the powder were measured, the average values were calculated, and the aspect ratio was calculated from the ratio of average particle size/average thickness.
[Flexural modulus (MPa)]
The measurement was performed according to ASTM D790 under the following conditions.
Temperature: 23℃
Test piece: 127 mm (length) x 12.7 mm (width) x 6.35 mm (thickness)
Bending speed: 30 mm/min
Span: 100cm

[IZOD impact strength (J/m)]
The IZOD impact strength was measured according to ASTM D256 under the following conditions.
Test piece: 63.5 mm (length) x 12.7 mm (width) x 3.2 mm (thickness) with notch Test temperature: -30°C
[Linear expansion coefficient (10 ^-5 /°C)]
The evaluation was carried out according to ASTM D 696 by the TMA method (measurement range: -30 to 80°C).
[Primerless adhesion test (90°C hot shear test)]
・Urethane adhesive
In the primerless adhesion test, a urethane-based adhesive was used in which a base component and a curing agent component prepared as described below were mixed immediately before adhesion.
(Preparation of main component)
Using a stirrer, 42.4 parts by mass of urethane prepolymer, 1.7 parts by mass of an isocyanurate of hexamethylene diisocyanate (Takenate D-170HN, manufactured by Mitsui Chemicals), 1.3 parts by mass of a mixture of an isocyanurate and allophanate of pentamethylene diisocyanate (STABIO D-376N, manufactured by Mitsui Chemicals), 20.6 parts by mass of carbon black (#200MP, manufactured by Shinnikka Carbon Co., Ltd.), 18.3 parts by mass of calcium carbonate (Super S, manufactured by Maruo Calcium Co., Ltd.), 15.5 parts by mass of a plasticizer (diisononyl phthalate, manufactured by J-Plus Corporation), and 0.2 parts by mass of a catalyst (dimorpholinodiethyl ether, manufactured by San-Apro Co., Ltd.) were stirred and mixed to obtain a main component of the adhesive.

The urethane prepolymer was synthesized by mixing 700 g of polyoxypropylene diol (average molecular weight 2000), 300 g of polyoxypropylene triol (average molecular weight 3000), and 499 g of 4,4'-diisocyanate phenylmethane (molecular weight 250) (NCO/OH=2.0 at this time), adding 500 g of diisononyl phthalate, and stirring the mixture at 80°C for 12 hours in a nitrogen stream to cause a reaction; the urethane prepolymer contained 2.10% isocyanate groups.
(Preparation of Curing Agent Component)
Using a stirrer, 45.9 parts by mass of trifunctional polypropylene polyol (Exenol 1030, manufactured by Asahi Glass Co., Ltd.), 5.0 parts by mass of polybutadiene diol (Poly bd R-45HT, manufactured by Idemitsu Kosan Co., Ltd., hydroxyl value: 0.8 mol/kg), 2.0 parts by mass of terpineol (manufactured by Yasuhara Chemical Co., Ltd.), 45.8 parts by mass of calcium carbonate (Kalfine 200, manufactured by Maruo Calcium Co., Ltd.), 1.0 part by mass of ion-exchanged water, and 0.1 part by mass of a catalyst (dimorpholinodiethyl ether, manufactured by San-Apro Co., Ltd.) were stirred and mixed to obtain a curing agent component for the adhesive.
- Preparation of test specimens and their surface treatment
Each polypropylene resin composition was injection molded using a mold cavity having a length of 350 mm, a width of 100 mm, and a thickness of 3 mm at a resin temperature of 210°C and a mold temperature of 40°C to obtain a flat plate, which was then cut into a shape of 100 mm x 25 mm x 3 mm to obtain a test piece for the primerless adhesion test.

The surfaces of the obtained test pieces were subjected to a surface treatment (flame treatment). A flame treatment device (Arcogas FTS 201) was used for the surface treatment. The flame treatment device can adjust the flow rate of the combustion gas and air.

For the surface treatment, the air flow rate was fixed at 100 L/min, the combustion gas (propane gas) flow rate was adjusted to 3.7 L/min, the distance between the plate and the flame irradiation head was 40 mm, and the treatment speed was 800 mm/sec to produce a surface with a surface free energy of 42 dyne/cm (mN/m) (surface treatment state: low treatment). Similarly, a surface with a surface free energy of 52 dyne/cm (mN/m) was produced with a distance of 30 mm and 800 mm/sec (surface treatment state: medium treatment), and a surface with a surface free energy of 64 dyne/cm (mN/m) was produced with a distance of 10 mm and 800 mm/sec (surface treatment state: high treatment).
・Preparation of laminated structure test pieces using primerless adhesion, 90℃ hot shear test
On each surface-treated test piece obtained above, an adhesive layer made of an adhesive was formed without a primer so that the adhesive area was 25 mm (width) x 10 mm (length) and the thickness was 5 mm, and glass (7.5 x 25 x 5 mm thick) was selected and used as the member on the other side of the adhesive layer, and cured at room temperature to obtain a laminated structure test piece in which a molded body made of a polypropylene resin composition, a resin cured layer obtained from the adhesive, and glass were laminated. After curing at room temperature for 3 days, the same surface treatment as described above was performed on the back side of the resin substrate side of each obtained laminated structure test piece, and a cationic electrodeposited steel plate having a thickness of 1 mm was bonded using an adhesive (WS-242 manufactured by Sika Hamatite Co., Ltd.), and after further curing at room temperature for 3 days, the glass was fixed as shown in the schematic diagram of FIG. 1 using a tensile tester in accordance with JIS K6850:1999, and the shear strength was measured at 90 ° C. and a tensile speed of 50 mm / min, and the average value of the four measured values was obtained as the hot shear test strength (MPa).

[Production Example 1] Preparation of propylene-ethylene block copolymer (A-1) (1) Preparation of solid titanium catalyst component 95.2 g of anhydrous magnesium chloride, 442 mL of decane, and 390.6 g of 2-ethylhexyl alcohol were reacted by heating at 130°C for 2 hours to obtain a homogeneous solution, to which 21.3 g of phthalic anhydride was added, and the mixture was further stirred and mixed at 130°C for 1 hour to dissolve the phthalic anhydride.

After cooling this homogeneous solution to room temperature, 75 mL of the homogeneous solution was added dropwise over one hour to 200 mL of titanium tetrachloride kept at -20°C. After the addition was completed, the temperature of this mixture was raised to 110°C over four hours, and when it reached 110°C, 5.22 g of diisobutyl phthalate (DIBP) was added and the mixture was stirred at the same temperature for two hours.

After the 2-hour reaction, the solid portion was collected by hot filtration, resuspended in 275 mL of titanium tetrachloride, and then heated again at 110°C for 2 hours. After the reaction was completed, the solid portion was collected again by hot filtration and thoroughly washed with decane and hexane at 110°C until no free titanium compounds were detected in the solution.

The detection of the free titanium compound was confirmed by the following method. 10 mL of the supernatant of the solid catalyst component was collected with a syringe and charged into a 100 mL sidearm Schlenk tube that had been previously substituted with nitrogen. Next, the solvent hexane was dried with a nitrogen stream, and then vacuum dried for 30 minutes. 40 mL of ion-exchanged water and 10 mL of (1+1) sulfuric acid were charged and stirred for 30 minutes. This aqueous solution was transferred to a 100 mL measuring flask through a filter paper, followed by the addition of 1 mL of concentrated _H3PO4 solution as a masking agent for iron (II) ions and 5 mL of ₃ % aqueous hydrogen peroxide solution as a color-developing reagent for titanium, and the measuring flask was then filled up to 100 mL with ion-exchanged water. The measuring flask was then shaken, and after 20 minutes, the absorbance at 420 nm was observed using UV, and the free titanium was washed and removed until this absorption was no longer observed.

The solid titanium catalyst component prepared as above was stored as a decane slurry, and a portion of this was dried in order to examine the catalyst composition. The composition of the solid titanium catalyst component thus obtained was 2.3% by mass of titanium, 61% by mass of chlorine, 19% by mass of magnesium, and 12.5% by mass of DIBP.
(2) Preparation of prepolymerization catalyst 100 g of the solid titanium catalyst component, 131 mL of triethylaluminum, 37.3 ml of diethylaminotriethoxysilane, and 14.3 L of heptane were charged into a 20 L autoclave equipped with a stirrer, and 1000 g of propylene was charged while maintaining the internal temperature at 15-20°C, and the reaction was carried out for 120 minutes with stirring. After the polymerization was completed, the solid component was allowed to settle, and the supernatant was removed and washed with heptane twice. The obtained prepolymerization catalyst was resuspended in purified heptane, and the concentration was adjusted with heptane to a solid catalyst component concentration of 1.0 g/L, to obtain a prepolymerization catalyst slurry.
(3) Main polymerization: 43 kg/hour of propylene, 256 NL/hour of hydrogen, 0.49 g/hour of the prepolymerization catalyst slurry produced in (2) above as a solid titanium catalyst component, 4.5 mL/hour of triethylaluminum, and 1.8 mL/hour of diethylaminotriethoxysilane were continuously fed into a 58 L jacketed circulation type tubular polymerization reactor, and polymerization was carried out in a liquid-filled state in which no gas phase was present. The temperature of the tubular polymerization reactor was 70° C., and the pressure was 3.57 MPa/G.
The obtained slurry was transferred to a vessel polymerization reactor equipped with a stirrer having an internal volume of 100 L, and further polymerization was carried out. To the polymerization reactor, propylene was supplied at 45 kg/hour, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 8.8 mol%, and polymerization was carried out at a polymerization temperature of 68° C. and a pressure of 3.36 MPa/G.

The resulting slurry was then transferred to a 2.4 L liquid transfer tube, where it was gasified and gas-solid separated. The polypropylene homopolymer powder was then sent to a 480 L gas-phase polymerization vessel, where ethylene/propylene block copolymerization was carried out. Propylene, ethylene, and hydrogen were continuously supplied so that the gas composition in the gas-phase polymerization vessel was ethylene/(ethylene + propylene) = 0.20 (molar ratio), and hydrogen/ethylene = 0.0031 (molar ratio), and polymerization was carried out at a polymerization temperature of 70°C and a pressure of 1.40 MPa/G.

The resulting propylene-based block copolymer was then vacuum dried at 80° C. The MFR (230° C., 2.16 kg load) of the propylene-ethylene block copolymer (A-1) thus obtained was 80 g/10 min, the amount of decane-soluble portion (propylene-ethylene copolymer component) was 7 mass%, the amount of decane-insoluble portion (propylene homopolymer component) was 93 mass%, and the intrinsic viscosity [η] of the decane-soluble portion was 7.5 dl/g.

Production Example 2 Preparation of Propylene Homopolymer (B-1) A solid titanium catalyst component was obtained in the same manner as in Production Example 1 (1) Preparation of Solid Titanium Catalyst Component.
(2) Production of prepolymerization catalyst 100 g of a solid titanium catalyst component, 39.3 mL of triethylaluminum, and 100 L of heptane were charged into a 200 L autoclave equipped with a stirrer, and while maintaining the internal temperature at 15 to 20° C., 600 g of propylene was charged and reacted with stirring for 60 minutes to obtain a prepolymerization catalyst slurry.
(3) Main polymerization: Propylene was continuously fed at 43 kg/hour, hydrogen at 177 NL/hour, the prepolymerization catalyst slurry produced in (2) at 0.58 g/hour as a solid titanium catalyst component, triethylaluminum at 3.1 ml/hour, and dicyclopentyldimethoxysilane at 3.3 ml/hour into a jacketed circulation type tubular polymerization reactor having an internal volume of 58 L, and polymerization was carried out in a liquid-filled state in the absence of a gas phase. The temperature of the tubular polymerization reactor was 70° C., and the pressure was 3.53 MPa/G.
The obtained slurry was transferred to a vessel polymerization reactor equipped with a stirrer having an internal volume of 100 L, and further polymerization was carried out. To the polymerization reactor, propylene was supplied at 45 kg/hour, and hydrogen was supplied so that the hydrogen concentration in the gas phase was 3.2 mol%, and polymerization was carried out at a polymerization temperature of 70° C. and a pressure of 3.28 MPa/G.
The resulting propylene homopolymer was then vacuum dried at 80° C. The propylene homopolymer (B-1) thus obtained had an MFR (230° C., 2.16 kg load) of 30 g/10 min.

Production Example 3 Preparation of Propylene Homopolymer (B-2) First, a prepolymerization catalyst slurry was obtained in the same manner as in Production Example 1 (1) Preparation of Solid Titanium Catalyst Component and (2) Production of Prepolymerization Catalyst.
(3) Main Polymerization To a 1,000-L vessel polymerization reactor equipped with a stirrer, 131 kg/hour of propylene, 0.70 g/hour of the prepolymerization catalyst slurry as a transition metal catalyst component, 19.6 mL/hour of triethylaluminum, and 4.2 mL/hour of diethylaminotriethoxysilane were continuously supplied, and hydrogen was supplied so that the hydrogen concentration in the gas phase became 5.3 mol %, and polymerization was carried out at a polymerization temperature of 75° C. and a pressure of 3.5 MPa/G.

The obtained slurry was sent to a 500 L vessel polymerization reactor equipped with an agitator, and further polymerization was carried out. Propylene was supplied to the polymerization reactor at 30 kg/h, and hydrogen was supplied to the polymerization reactor so that the hydrogen concentration in the gas phase was 3.9 mol%, and polymerization was carried out at a polymerization temperature of 74.5°C and a pressure of 3.4 MPa/G.

The resulting slurry was then sent to a 500 L vessel polymerization reactor equipped with an agitator for further polymerization. Propylene was supplied to the polymerization reactor at 20 kg/h, and hydrogen was supplied to the polymerization reactor so that the hydrogen concentration in the gas phase was 3.4 mol%, and polymerization was carried out at a polymerization temperature of 73°C and a pressure of 3.4 MPa/G.

The resulting slurry was then deactivated, vaporized, and subjected to gas-solid separation. The resulting propylene homopolymer was vacuum dried at 80°C. The MFR (230°C, 2.16 kg load) of the propylene homopolymer (B-2) thus obtained was 210 g/10 min.

[Ethylene/α-olefin copolymer]
As the ethylene/α-olefin copolymer (C-1), TAFMER (registered trademark) A4050S manufactured by Mitsui Chemicals (ethylene content = 80 mol%, 1-butene content = 20 mol%, MFR (230°C, 2.16 kg load) = 7 g/10 min, density = 0.862 g/cm ³ , melting point peak = less than 50°C) was used.

As the ethylene/α-olefin copolymer (C-2), TAFMER (registered trademark) A1050S manufactured by Mitsui Chemicals, Inc. (ethylene content = 80 mol%, 1-butene content = 20 mol%, MFR (230°C, 2.16 kg load) = 2 g/10 min, density = 0.862 g/cm ³ , melting point peak = less than 50°C) was used.

As the ethylene/α-olefin copolymer (C-3), ENGAGE (registered trademark) 11547, a polyolefin elastomer manufactured by Dow Chemical Company (MFR (230° C., 2.16 kg load)=9 g/10 min, density=0.866 g/cm ³ , melting point peak=120° C.), was used.

[Inorganic filler]
As the inorganic filler (D-1), talc having the following properties was used.
(D-1): Talc, average particle size (laser diffraction method) = 6.0 μm, aspect ratio (SEM measurement) = 7.0

[Examples 1-2, Comparative Examples 1-2]
The propylene polymer (A), propylene homopolymer (B), ethylene-α-olefin copolymer (C) and inorganic filler (D) were mixed in the amounts shown in Table 1 and extruded using a twin-screw extruder (TEX (registered trademark) 30α, manufactured by The Japan Steel Works, Ltd.) under conditions of a cylinder temperature of 180°C, a screw rotation of 750 rpm and an extrusion rate of 60 kg/h to obtain polypropylene resin compositions. The melt flow rate (230°C, 2.16 kg load) of each of the obtained polypropylene resin compositions is shown in Table 1.

Each of the obtained polypropylene resin compositions was injection molded using a mold cavity having a length of 350 mm, a width of 100 mm, and a thickness of 3 mm at a resin temperature of 210°C and a mold temperature of 40°C to obtain a flat plate, which was then cut into a shape of 100 mm x 50 mm x 3 mm to obtain a molded specimen for primerless adhesion testing. In addition, molded specimens for measurement having the above-mentioned shape were obtained by injection molding and cutting at the same resin temperature and mold temperature.

Using the obtained molded test pieces, the flexural modulus, IZOD impact strength, and linear expansion coefficient were measured by the above-mentioned test methods. In addition, the 90°C hot shear test strength was measured by the above-mentioned primerless adhesion test. The results are shown in Table 1.

表１に示す結果から明らかなように、融点ピークが１１０℃以上という高融点を有するエチレン・α－オレフィン共重合体を含むポリプロピレン系樹脂組成物からなる成形体は、機械的物性に優れるとともに、プライマーレス接着試験では、接着剤が硬化した層と強固に接着されており、９０℃という高温条件下においても高い接着強度を有することがわかった。

As is clear from the results shown in Table 1, a molded article made of a polypropylene resin composition containing an ethylene/α-olefin copolymer having a high melting point with a melting point peak of 110°C or more has excellent mechanical properties, and in a primerless adhesion test, it was found to be firmly bonded to a cured layer of the adhesive and to have high adhesive strength even under high temperature conditions of 90°C.

Possible industrial applications

The polypropylene-based resin composition of the present invention and its molded articles can be suitably used for applications such as automobile interior materials such as door trims, instrument panels, ceilings, console boxes, pillars, glove boxes, etc.; automobile exterior components such as bumpers, side guards, air spoilers, side protectors, fenders, door panels, tailgates, etc.; home appliance parts, building materials, and other industrial parts.

Claims (8)

5 to 22 parts by mass of a propylene polymer (A) having a melt flow rate (230° C., 2.16 kg load) of 50 to 150 g/10 min and a decane soluble content of 6 to 15 mass %,
20 to 30 parts by mass of a propylene homopolymer (B) having a melt flow rate (230° C., 2.16 kg load) of 10 to 500 g/10 min,
23 to 30 parts by mass of an ethylene/α-olefin copolymer (C) which is a random copolymer of ethylene and an α-olefin having 4 to 8 carbon atoms and has a density of 0.850 to 0.880 g/cm ³ , a melt flow rate (230° C., 2.16 kg load) of 0.5 to 30 g/10 min, and a melting point peak of 110° C. or higher, and 30 to 40 parts by mass of an inorganic filler (D) (wherein the total amount of components (A) to (D) is 100 parts by mass).
A polypropylene resin composition comprising: The polypropylene resin composition according to claim 1, characterized in that the propylene polymer (A) is a block copolymer of propylene and ethylene, and the intrinsic viscosity [η] of the decane-soluble portion of the copolymer is 2 to 9 dl/g. 2. The polypropylene resin composition according to claim 1, wherein the inorganic filler (D) is talc and has an aspect ratio of 3 or more and less than 15. The polypropylene resin composition according to claim 1, characterized in that the 90°C hot shear test strength exceeds 1.5 MPa in a primerless adhesion test. The polypropylene resin composition according to claim 1, which is used for automobile exterior components. A molded article made of the polypropylene resin composition according to any one of claims 1 to 5. The molded body according to claim 6, which is an injection molded body or a press molded body. The molded article according to claim 6, which is an automobile exterior component.

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